Crude emulsions are formed when oil and water are intimately mixed together. This occurs in the near well bore, production tubing, wellhead, across valves and in pumps. These emulsions cause many problems for the oil and gas producer and have to be broken or demulsified, allowing the salt water component of the emulsion to be separated and removed. This enables the produced oil to meet BS&W (basic sediment and water) and salt specifications.
The dehydration of petroleum emulsions is generally accomplished by techniques such as settling, heat treatments, centrifuging, and application of electrical fields and addition of chemicals, i.e. demulsifies. The use of demulsifies has proven most effective in resolving crude emulsions.
Prior art demulsifies are mostly polymeric surfactants such as copolymers of ethylene oxide and propylene oxide, typically EO-PO-EO block copolymers, or alkyl phenol-formaldehyde resins or blends of various surface-active substances. These compounds are none-biodegradable and some are very toxic such as those with phenol group. Due to more and more severe environmental and ecotoxicological constraints, currently the challenge and requirement to use biodegradable and low toxic demulsifiers is strongly increasing in the oil production industry.